Time-limit starting and controlling rheostat.



PATBNIED FEB. 28, 1905.

R. H. READ & W. G. YATBS.

TIME LIMIT STARTING AND GONTROLLING RHEOSTAT.

APPLICATION FILED JULY 21, 1904.

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No. 783,462. K Patented February 28, 1905.

UNITED STATES PATENT OErice.l

ROBERT H. READ AND WILLIAM C. YATES, OF SOHENEOTADY, NEV YORK, ASSIGNORS TO GENERAL ELEOTRO COMPANY, A. CORPORATION OF NEWT YORK.

TIME-LIMIT STARTING AND CONTROLUNG Pil-iEOST/-t'il SPECIFICATION forming part of Letters Patent No. 783,462, dated February 28, 1905.

pplieation filed July 2l, 1904. Serial No. 217,440.

T U17/ 'ffl/71107171 "my 00720077 strip l1. The brushes 4 and iO are insulated Be it known that we, ROBERT H. READ and from the arm 3. i/VILLIAM O. YATEs, cltizens of the United ln line with the segment l1 is a set ol con- 50 States, residing at Schenectady, county of tact segments or buttons i9, connected with 5 Schenectady, State of New York, have inthe coils i3 of a lield-regulating resistance. vented certain new and useful Improvements A self-opening switch-arm 14 is pivote/.l to in Time-Limit Starting and OontrollingRhcothe panel l at 15 and carries a contact i6, stats, of which the following is a specification. which cooperates with a stationary clip 17. 55

This invention relates to rheostats for start- This constitutes the circuit-Ineaker for the IO ing and controlling' variable-speed electric main circuit. 1t is rendered automatic by a motors; and its object is to provide a device retaining-magnet i8 of the usual construction. of this kind in which the operator will be pre- A quickbreak switch if) is pivoted near the. vented from holding' the switch-arm for any main switch-arm and closes on a contact-stud eo length of time upon an intermediate point of 19. lt is operated by an insulated lug 2O on I5 the starting' resistance, and thereby damaging said arm just after themain brush leaves the the apparatus by the excessive heating of the lirst starting-segment6in moving' to the oil' coils. There is a proper speed of movement position on segment The reversing-switch for the switch-arm of a starting-rheostat, and comprises two insulated switch -blades 2i 6 5 the present invention enforces on the oper- 2l', mountedonapivotedhubQQ, ofinsulation,

2O ator an observance of this speed by open-cir and operating' to bridge the opposite pairs ol cuiting the retaining-magnet of a main circontact-clips 23 23 24 24 or the clips 25 25 26 cuit-*breaker incorporated in the apparatus if 26 by `giving' the hub aquarter-turn. This he actuates the arm too slowly. switch is intel-locked with the main switch- 7o Tn the accompanying' drawings, Figure l is arm, a spring-retractial bolt 2T being lorced a front elevation of the apparatus. Fig'. 2 is into notches in the hub 22 by a cam 23 on the a diagram of circuits, and Fig. 3 is a detail side hub of the main arm except when the latter elevation of the main brush. is in the ofi' position, at which time the bolt The working' parts are mounted on a suitis retracted and the reversing-switch `can be 7F able panel l, through which passes a shaft 2, shifted. An overload-soleuoid 2%) operates a 30 to which is secured an arm 3, carrying` a lamibridging-contact 30, which opens the circuitnated brush 4, one end of which makes conbreaker i4 by opening' the circuit of the retact with a number of contact-segments artaining-magnet 18 at the contact-studs 3 '30'. ranged concentric with the shaft. The lirst This magnet can also be short-circuitcd in 8o segment 5 is deadf7 The next few segments order to open the circuit-brealwr by a time 6 are those connected with the coils 6' of the limiting device which constitutes the novelty starting resistance. The succeeding segments of the presentinvention. Aleverl is pivoted 7 are connected with the coils 7 of the runconcentricwith the main switch-arm 3, and its ning or controlling' resistance. The other end outer end is connected by a red 32 with a time 8* of the brush 4 bears on along broad segment limiting' device, preferably a dash-pot 33. A

40 8, which is cut away at the left-hand end to spring' 34 tends to lift the lever at a rate govmake room for a short insulated segment 9, erned by the dash-pot. The lever carries an the gap between these two segments being insulated bridging-contact 35, coi'perating bridged by the wide end of the brush 4 when with two lixed contact-studs 36 A horn 9o it stands over them, as shown in Fig. 3. The 37 on the main switch-arm 3 strikes the lever arm 3 also carries a light spring-brush 10, and forces it downward when the switch is electrically connected with the main brush turned to the otl' position compressing the and bearing' on a long contact segment or spring 34 and separating the contact from the studs 36 36. preierably carrying an antit'riction-roll 39, strikes the circuit-breaker 14 and closes it when the arm 3 is moved to the extreme lett.

The circuits are as follows: The line-torminals are seen at 40 @C0/ The held-coil ot' the motor is connected with the studs 111 41' and the armature with the studs 112 4Q. Terminal 41,0 is connecte ddirectly with the clip 1T. Terminal 4() is connected with iield-stud 41' and also with the contact-stud 30.A 1t is also connected with the clips 23 Q4. rlhe clips 25 26 are connected, through the overload-solenoid 29, with the last segment 7. The clips 23 25 are connected with the armature-stud 42 and the clips L4 26 with the stud 4Q'. The iieldstud 41 is connected with the contact-strip 11. rlhe lirst starting-resistenee segment 6 is connected with the linal field-resistance segment 12 and also with the contact-stud 19'. The quick-break switch 19 is connected with the contact-strip 8, and the latter is connected, through the pivot 15 ot the circuit-breaker 141, with one terminal ol the retaining-magriet 1S. The other terminal of said magnet is connected, through a resistance 3, with the contact-stud 30. ltis also connected with the contact-stud 36, the other stud, 36', being connected with the contact-segment 9.

The operation is as follows: lVhen the switch-arm 3 is moved to the extreme left, the roll 39 strikes the circuit-breaker 1st and closes it upon the clip 17, thereby completing' the circuit through the retaining-magnet1S by way oi' the resistance 43, contact-studs 302 30, and contact 30. The circuit of the motor is still open, however, at the interval between the dead segment 5 and the lirst starting-segment 6 and also at the quick-break switch 19, which has been swung away from the contact-stud 19 by the lug 2O on the main arm 3. The movement of the arm 3 has also forced down the lever 31 and compressed the spring 34 and opened the short-circuiting contact It has also released the spring-bolt 27 and unlocked the reversing-switch. The latter having been thrown to -give the desired direction of rotation to the motor, the arm 3 is moved to the right, locking the reversingswitch again. l ust before the brushes pass onto the iirst starting-segment 6 the switch 19 closes the motor-circuit, so that all sparking takes place at the contact 19, and thus the brushes are protected. Now that the horn 37 has been withdrawn from the lever 31 the spring begins to litt said lever, being retarded by the dash-pot, which is set to allow a given timesay thirty'secondsto elapse before the contact will bridge the studs 36 36". Dur ing this time the operator must move the arm 3 over the starting-segments G and the eontact-segment 9 and reach the running-segments 7 and the contact-strip 8. lf he is too slow and is caught with the brushes on the i segment 9 when the contact 35 closes, the rei A lug 38 on the main arm, l taining-magnet 1S is short-circuited by way ot' the contacts 35 36 236/, segmenti), brush Lle, strip 8, and pivot 15. This releases the circuit-breaker, which can be reset only by returning the main arm to the extreme lett.

1n case of an overload the solenoid 29 lifts the contact 30 otl the studs 30' 30, and thus breaks the circuit ol' the no-voltage magnet 18.

To stop the motor, the arm 3 is moved back to the dead segment The circuit-lneaker opens the instant the arm makes contact with the strip 9, which is be'lore the brushes leave the iirst ot' the starting-segments (S. lNhen the motor is running, the held-coil and armature are in multiple, each having its own resistance in circuit; but when the arm 3 is turned back to the segment 5 and the circuitbreaker is open the ield-coil and armature are placed in a closed circuit in series with each other and with all the resistances, so that the motor, running as a generator by its own momentum, quickly comes to rest.

1V hat we claim as new, and desire to secure by Letters Patent of the United States, is

1. The combination with a rheostat comprising starting and running resistances, ol a circuit-breaker, and means for tripping said circuit-ln'eaker within a predetermined time if the operator Vfails to move oli the starting resistance within said time.

2. The combination with a rheostat comprising starting and running resistances, ol a circuit-breaker, and means for tripping said circuit-breaker within a predetermined time itl the operator itails to move ol'l" the starting resistance within said time, said means comprising a dash-pot and a switch controlled thereby.

3. The combination with a rheostat comprising' starting and running resistances, olE a circiiit-ln'eaker, and means lor tripping said circuit-breaker within a predetermined time it' the operator tails to move oli' the starting resistance within said time, said means comprisingI a short circuit containingtwo breaks, one controlled by the rheostat-arm, a switch controlling the other break, and a dash-pot governing the closing olf said switch.

41:. The combination with a rheostat comprising' a switch-arm, ot' a circuit-breaker comprising a novoltage retaining-magnet. a switch for short-circuiting said magnet adapted to be opened by said arm, andl a dash-pot controlling the closing o1l said switch.

5. The combination with a rheostat comprising a switch-arm, of a circuit-lneaker comprising a no-voltage retaining-magnet, a short circuit lor said magnet controlled by said arm, a switch in said short circuit adapted to be opened by said arm, and a dash-pot controlling the closing oll said switch.

6. rl`he combination with a rheostat comprising a switch-arm, ol a circuit-b reake r comprising a no-voltage retaining-magnet, a short circuit lor said magnet controlled by said arm,

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a lever pvoted concentric with said arm and earrylng a Contact controlling said short 01reuit, means whereby said arm can actuate said lever, and a dash-pot Connected with said lever. y

7. The combination with a rheostat comprising a switch-arm, of a switch adapted to be opened by said arm when moved to the off position, a dash-pot controlling` the closing of said switch, and a circuit-breaker controlled by said switch.

8. The combination with a rheostat comprising a starting' resistance and a running resistance, of a switch-arm cooperating therewith in succession, a circuit-breaker comprising a 11o-voltage retaining-magnet, a short circuit for said magnet which is opened when said arm rnoves off the starting resistance, a 

